Gantry crane



Jan. 5, 1965 R. w. ERLBACHER GANTRY CRANE 2 Sheets-Sheet 1 Filed July 2ll 1961 Jan. 5, 1965 R. w. ERLBACHER 3,164,105

GANTRY CRANE Filed July 2l. 1961 2 Sheets-Sheet 2 Z nz 52 H2 92 POSITION 0F TRUCKS 0N CURVD SECT/0N 0F TRACK WIDTH BETWEEN CRANE TRUCK CENTERL/NES 0F CURVED SECT/ONS 0F TRACK TORNEYS United States idea-,1195 GANIRY CRANE Robert W. Erlbacher, 920 N. Fountain, Cape Girardeau, M0. Fiied .Iuiy 21, 1961, Ser. No. 125,767 6 Ciaims. (Cl. ll5 27) This invention relates to improvements in gantry cranes and, in particular, is concerned with improvements in the supporting frame and wheeled trucks supporting the frame and which are adapted to engage a track having sharp radii.

It has been a problem in the past to provide gantry cranes that are adapted to be supportedby steel wheels and which move along tracks on loading docks and the like where there are sharp curves. By means of this invention there has been provided a gantry frame-having trucks supporting wheels therein in which the trucks are adapted to shift axially as the gantry crane moves around a sharply curved track. The movement of the wheels and the trucks compensates for varying positions of the trucks with respect Vto the track to `account for changed movement along the curve.

It is afurther feature of this invention to provide wheeled trucks supporting a gantry frame in which lthe trucks can move laterally with respect to the frame and hug a supporting rail by means of doubly flanged wheels, which provide a self steering vfeature for the gantry frame.

It is still another feature of this invention that the gantry frame is provided with trucks which are supported from the gantry frame in such a manner that .they may oscillate somewhat about a horizontal axis to accommodate for unevenness in the rails upon which the gantry rides and also wherein the trucks can move'laterally to `a slight degree to compensate for distance between centers as the frame rounds a sharp curve.

It is another feature of this invention that a specially designed gantry track is employed in combination with Patent the gantry using. the trucks that can move slightly laterally.Y The trackis designed using the inner rail of the track at a constant radius, while the outer rail of the trackjis an average of thetracing of the outerffront truck center of the `gantry frame and the outer rear truck center, lItwill be understood thatv two tracings are obtained with'. the frontoutside truck center givinga tracing that-is of a larger diameter than the rear truck'center tracing. The

average is determined by merely taking the ditferencebe-- tweenpthe inner and outer tracings. i

It is still another feature of this invention that a gantry frame is provided in which motorized trucks are employed for the gantry frame withthese truckshaving wheels that closely hug a gantry track and which are adapted to oscillate and'shift laterally. to provide for lirregularities and 4are best shown in FIGURES 2 through 9.y Particular' curves in the track, and to obtain self steering ofthev gantry by providing doublyanged gantry wheels.

Other objects of Athis invention will appear in the detailed description which follows and will be otherwise ap' parent to those skilled in the art.

.For the purpose of illustration there is shown in the accompanying drawings a preferred embodiment of this,

invention. It is to be understood that these drawings are for the purpose of example only, however, and that the` "ice of FIGURE 1 showing the trunnion mounting for the right front truck;

FIGURE 3 is a front elevation view of the truck shown in FIGURE 2;

FIGURE 4 is a side view taken from the left side of FIGURE 3 showing the truck;

FIGURE 5 is a side View taken from the right side of the truck of FIGURE 3; v

FIGUREI 6 is an enlarged View in section taken on the line 6 6A of FIGURE 2 showing the trunnion construction and the driving means for the wheels;

FIGURE 7 is a View in section taken on line 7 7 of FIGURE 6 showing the rear wheel structure and means for connecting it to a motor drive shaft sprocket;

FIGURE 8 is a view in section taken on the line 8 8 of FIGURE 6 showing thestructure of the front wheel;

'FIGURE 9 is a view in section taken on the line 9 9 of FIGURE 6 showing the trunnion structureffor mount ing the truck housing to the bottom of the gantry frame leg;

FIGURE 10 is a schematic diagram showingthe gantry I frame and .truckspositioned on anarrow curve; and

FIGURE 11 is a schematicpdiagram showing the positioning of the gantry frame and its wheels on a transition curve between the straight portion of the track' and the fully curvedportion just as the frame rounds the curve with means for laying out a special curve that is an average between ythe tracing of the right front truck center and right rearv truck center.

The gantry crane is best shown in FIGURE 1 and is generally indicated by the reference numeral 2i). It has the usual boom 22 and is mounted upon a rotary platform 24 supported by a gantry frame 26. The gantry frame has a left front leg not shown, a right front leg 30a left rear leg not shown, and a right rear leg v34. Theselegsfn entire crane is'mounted upon gantry tracks 46. l

The trunnion Ymeans 36 and the structure of the trucks reference for .the structure ofthe. trunnion-structureds madeto FIGURES 2,'3, 6 and 9. Thus, the trunnion is comprised of a Tlf-shaped Vtrunnion knuckle-element 48. The element 48, as shown in FIGURE 6, iscomprised of a shaft portion 50 and a hub-shapedbearing portion 51 which is retatabiy supported within the ieg se, 'as shown i -for the right frontfg'antry frame leg in FIGURE 6. .This

support is provided-'by/means ofa top support plate 52 and a bottom support plate 54 spaced. from one another by a protective sleeve 5S; Van end washer S6 iitting around a cap `screw57 threadedlyreceived within an opening at the top of the shaft: portion holds the end'of said Shaft portion `in place while permitting rotation.

The bottom of the knuckle element 4S?V is provided with the Vbearing portion 51 having'a shoulder 58 which, through spring washer 59 and bearing 61, 'engages' the A "bottom support plate'. t The journal portion rotatably'receives a truck housing connecting shaft 6i). The ends of thel shaft et) are inv turn journaled within the sidesof' the' truck housing described below. By means of the above structure,`the knuckle element through the shaft Sil'can pivot aboutV the verticalaxis of the shaft with respect tor the leg to provide forturning of the truck housing with respect to the leg. Also, by `means of the shaft 60, re-

ceivedwithin the bearing portion 51, the` truck housing. may oscillate back and forth [to 'accommodate for irregu-v p laritiesin the track.

yT'netrucks 38, 4t), 42 and 44 are all of vsimilar clon-i struction and for the purpose of convenience only the right front truck 4t! will be described. It will be understood that only this truck may be motorized, or, where additional power is desired, all of the trucks may be provided with motors to provide power for `moving the wheels located within the trucks;

The truck 40 is comprised of a housing 62, which receives, in journalled relation in its sides, the support shaft i6d passing `through the bearing portion of the knuckle element connecting the truck to the gantry'leg The housing has a central opening 64 at the top wall toV provide for a slight =degree of oscillation'of the housing with respect to the leg and permit some freedom of movement of the knuckle element passing therethrough.

The truck-40 is further provided with a pair of front and rear wheels 68 and 70 connected in tandem. The front v truck by an axle 74. Both of the wheels are identical in construction and Veach has a pair of circumferential inwardly beveled flanges 76 and 78 which merge into a track bearing surface Si). This construction provides for self centeringy and self steering ofthe wheels as they pass along the track and provide for guiding of the truck along the curved sections of the track.

In order to provide for prime movement to the wheels a motor 84 is 'mounted to the rear of the truck housing 62. This is best shown in FIGURES 3 and 4. The motor has ashaft 86 connected to a sprocket gear SS and a sprocketychain 90 passing through openings 92 and 94- in the rear wall of the housing provides power to the'rear wheel 70. This power is effected by a sprocket wheelz 95 keyed tothe axle 74. A take-off sprocket chain 98 provides for imparting power to the front wheel 68 by connections to sprocket gears lil@ and lib2'connected to the rear and front axles 74 and 72, respectively.

Y Y USE Y vThe gantry frame and the wheeled trucks of this inlvention may bev simply constructed according to the structuresy described. The trunnion mounting means provides for pivoting of the trucks with respect to the leg through the shaft portion Si). Likewise the shaft d@ connecting' the housing to the trunnion knuckle element provides for a degree of oscillation of the housing 'with respect `to the frame to accommodate virregularities in the track.

. VThus by the structure ldescribed the tandem wheels in thehousing can be` turned.' about a vertical laxis and can also be turned about; a horizontal axis toa slight degree. Self steering is effected bythe doubly anged wheels whichare vguided, along the gantry track.

As an important feature of the invention to provide for lateral movement of the wheels with respect to the gantry frame the trunnion mounting'means has an axial vor lateral degree of movement' to providejfor self alignment and steering. Particular reference will bemade to FIG-V URE 9 where it will be seenkv that the bearing portion of the Vtrunnion v'knuckle clement hasan endv ,11,0 spacedfrom the inner side wall H2 ofthe housing. This condi tionis also true for the opposite sideof the'bearing por# tion and-the opposite 'inner side wall," asy FIGURE 9 shows a centered position. l".l`hu's,'the trucky may move in an axial direction back and forth with respect to the Y bearing and portion 11i), as is apparent from FIGURE 9.VA

By' this means shortening or' effective lengthening of the distance between the left landpright trucks at. the front ofthe'y gantry frame and' between the left and'right trucks at the rear of the gantryrameV may be eiected. This is particularly valuable when the lgantry is moved around sharp curves, a'szwill be more fully discussed below.

The above structure, Vwhen motorized with the truck mounted motor, `provides a' very effective means for mov` ing a gantryfalong gantry ',track's. vIn.addition`to the single motor (shown, it will be readily understoodthat adtrollcd in an obvious manner by providing the usual connections to the gantry crane to be operated by a gantry operator in the cab.

Reference will now be made to the operation of the wheels of the gantry frame on the curves of FIGURES 10 and ll. FIGURE l() shows a curved track i6 having an inner rail-IIS of a constant radius, which, for purpose of example, may be feet. The outer rail lill is also of a constant radius, which, for purpose of example, may be 88 feet giving an effective gauge of 38 feet. The distance between the normal centers of the front left and right trucks 3Sand 44B is 4() feet, which is the same distance between the front legs as well as the rear legs. Because of the askew relationship of the trucks at the front and the rear, they accommodate the effective gauge of 38 feet. This gauge of 38 feet is 2 feet smaller than the axial distance between the normal centers of the trucks at the front and the rear.

The problem in designing the trucks for the crane and in designing the curve rests in moving the gantry from a straight section of track with a gauge of 4G into the curve section with a gauge of 3S feet. FIGURE ll shows a convenient means for designing such a transition curve to accommodate the axially movable trucks mounted upon the gantry crane. The bottom portion of tracks IIS and in FIGURE ll has a straight portion of 40 feet gauges generally indicated by the reference numeral 122, while the beginning or transition portion of the curve is designated portion i242-, and the completely curved section 126 is shown at the top portion of the drawing and will be understood as being the same as shown in FIGURE 1G. The inner track 118 in the transition portion is held constantly on the 50 foot radius. By moving the gantry crane, or a representation of it, in Working out the curve along the inner rail and plotting the position of the outer wheels, in this case the right front truck center 40 and the right rear truck center 44, two separate curves are obtained, one for the front right truck and other for the rear right truck. In this case, the outer curve is designated 128 and is traced by the center of the right front truck 4d, while the inner'curve 139 is traced by the center of the right rear truck 44. By averaging the two rcurves the shape of the transition track is effected and this average curve is designated 1.32 located midway between the inner Y that is 41/2 for the inside or left front truck 3S and 41/2" for the outside truck that is the right front truck 4t). The back or rear trucks must increase approximately 9 inches betweedcenters or 41/2" for the inside or left rear truck l 42 and 41/2 for the' outside or right rear truck 44. It

willA be understood that the dimensionsY listed are, of course, for the purpose of example only and are given to show the accommodation of the gantry upon very tight InFIGURE ll the axis of the front trucks is shown in Y .bold black lines indicated 163, while the axis ofthe rear trucks is indicated by the bold black Aline 14%. In general, the lines indicated to 150 indicate the axis of v the rear trucks as they move from the straight track section 122 into the transition curve 124, while the lines i60 to 17d indicate the axis of the front truck for each respective position along the tracks. By means of this invention there has been provided a simply designed and durable` truck system for a gantry crane. The trucks may be simply motorized by a hydraulic motor with a high ratio box and gear chained drive to the wheels in which control can be simply, effected by a cab operator. The trucks are provided with means for permitting the axial or lateral movement to accommodate the necessary play when the crane moves Vinto a curve. The trunnion bearing some structure and quite high center of gravity, rela-v.

tively slow moving and are self contained,A and, as a result thereof, the invention of the truck system and the provision of the specially designed tracks described has provided a very advantageousV advance inthe art.

Various changes and modifications may be vmade within this invention as will be apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims appended hereto.

What is claimed is:

1. A gantry crane frame having four legs supported'by four rectangularly positioned trucks, said trucks each cornprising a housing, a pair of axles journalled in tandem in said housing, a pair of wheels carried in tandem upon said axles and each of said wheels having a pair of axially spaced circumferential iianges adapted to contact the opposite sides of a track upon which the crane may be carried and'shaft means to permit axial shitting of said wheels with respect to the gantry legs to iaccommodate tracks of varying gauge, said shaft means` connecting said trucks `to said legs for rocking movement about a horizontal axis,

said last named means comprising a bearing element connected to the bottom of a gantry leg and a shaft secured at its ends to said housing and received Within said bearing element in rotative relationship at an intermediate portion.

2. A gantry crane frame having four legs supported by four rectangularly positioned trucks, said trucks each cornprising a housing, an axle journalled in said housing, a

wheel carried by said axle and said Wheel havinga pairV of axially spaced circumferential iianges adapted to contact the opposite sides of a track uponv which the crane may be carried, means mounting said, truck housing -to a leg in pivotal relation about a verticalaxis to'efect turnaxial shifting of said wheels withv respect to the4 gantry Vlegs to` accommodate tracks of varying gauge, saidflast namedmeans comprising a bearing element connected to the bottom of a gantry' leg and receiving in laterally sliding relation a shaft Vparallel to the wheel axle andsecured to opposite side walls of said housing, said bearing element having a widthless thank that of thel distance between the walls of said housing wherebyv relative slidingmovement of the housing with respect to said gantry leg may bc eected. Y

3. A gantry crane frame having four legs supported by four rectangularly positioned trucks, said trucks eachV comprising a housing, `an axle journalled in said housing, a wheel carriedby said axle and said Wheel having a pair of axially spaced circumferential flanges adapted to contact the opposite sides of a track upon which the crane garitry leg at its upper end, and shaft means on said truck to permit axial shifting of said wheels with respect to the gantry legs toaccommodate tracks .of varying gauge, said connecting the truck housings to said legs for relative q i rocking movement about a horizontal axis, said wheels having a pair of axially spaced circumferential flanges adapted to contact the opposite sides of a track upon which the crane may be carried, means mounting said truck housing to a leg in pivotal relation about a vertical axis to effect turning ofthe crane rand shaft means to permit axial shifting of said wheels with lrespect to the gantry legs to accommodate tracks of varying gauge.

5.v A gantry crane frame having four legs supported by four rectangularly positioned trucks, said trucks yeach comprising a housing, a pair of axles each carrying a wheel journalled in tandem in said housing, shaft means connecting the truck housings to said legs for relative rocking movement about a horizontal shaft secured to the housing in parallel relation to said axles, said "shaft having a sliding surface substantially equal to the distance between the walls of said housing, said wheels having a pair of axially spaced circumferential tlanges adapted to contactv and secured for rotation relative to the bottom of the gantry leg at its upper end, and shaft means to permit axial shifting of'said wheels with'respect to the gantry legs to accommodate tracks of varying gauge,` said last named means comprising a bearing element connected to the bottom of said vertical shaft and receiving in laterally slidv ing relation the aforementioned horizontal shaft secured inside the housing to opposite side walls of said housing, said bearing elcmenthaving a width lessj than that of the distance between the Walls of said 'housing whereby relative sliding movement of the housing with respect toV said gantry leg may be effected;

Y ing of the crane, and shaft means on said trucks to permit 6. Agantry crane frame having fourilegssupportedby four iectangularly positioned trucks, said trucks each com- Y prising a housing, a pair of'axles each carrying a wheel journalled in tandem in saidV housing, shaft means connecting the truck housings to said legs forlrelative rocking movement about a horizontal shaft'jsecured to the last named means comprising a bearing element connected to the bottom of said vertical shaft and receiving in laterally sliding relation a shaft parallel to the wheel axle and v secured to said housing. v

4. A gantry crane frame having four'le'gs supported by four rectangularly positioned trucks, said truckseach comprising a housing, a pair of axles each carryinga housing in parallel relation to said axles, said Wheels having apair of axially spaced circumferentialilanges adapted to contactthe opposite sides of a trackupon Whichfthe crane may be carried, means mounting said truck housing ing to a leg in pivotal relation about a vertical axisl to permit turning of the crane, said means comprising a vertical shaft element connected at a lower endY to' said truckv housing and secured for rotation relative to the bottom of the gantry leg at its upper end, and means to permit am'al shifting ot said wheels with respect to the gantry legs to accommodate tracks kof Varying gauge, said last named means comprising any element connected 4to the bottom of said vertical shaft and receiving in laterally sliding rela-v tion the aforementioned horizontal shaft secured to said housing, and means for propelling said crane along the track comprising a motor mounted upon one of said trucks and having means connecting a power shaft of said motor to a firstone of said axles and power take off means connecting said lirst axle with the second axle.

- p nera-ms cites in the fue of this patentY UNITED-STATES PATENTS 782,034 Johnston l Feb. 7,r 1905 2,209,392 edwards July so, 1940 2,526,307 yards oct. 17', 1950 2,595,992 ."rapp\e1a1.g May 6, 1952 2,955,546 Liebherr et al. oct. 11, 1960 FOREIGNY PATENTSv- 

6. A GANTRY CRANE FRAME HAVING FOUR LEGS SUPPORTED BY FOUR RECTANGULARLY POSITIONED TRUCKS SAID TRUCKS EACH COMPRISING A HOUSING, A PAIR OF AXLES EACH CARRYING A WHEEL JOURNALLED IN TANDEM IN SAID HOUSING, SHAFT MEANS CONNECTING THE TRUCK HOUSINGS TO SAID LEGS FOR RELATIVE ROCKING MOVEMENT ABOUT A HORIZONTAL SHAFT SECURED TO THE HOUSING IN PARALLEL RELATION TO SAID AXLES, SAID WHEELS HAVING A PAIR OF AXIALLY SPACED CIRCUMFERENTIAL FLANGES ADAPTED TO CONTACT THE OPPOSITE SIDES OF A TRACK UPON WHICH THE CRANE MAY BE CARRIED, MEANS MOUNTING SAID TRUCK HOUSING ING TO A LEG IN PIVOTAL RELATION ABOUT A VERTICAL AXIS TO PERMIT TURNING OF THE CRANE, SAID MEANS COMPRISING A VERTICAL SHAFT ELEMENT CONNECTED AT A LOWER END TO SAID TRUCK HOUSING AND SECURED FOR ROTATION RELATIVE TO THE BOTTOM OF THE GANTRY LEG AT ITS UPPER END, AND MEANS TO PERMIT AXIAL SHIFTING OF SAID WHEELS WITH RESPECT TO THE GANTRY LEGS TO ACCOMMODATE TRACKS OF VARYING GAUGE, SAID LAST NAMED MEANS COMPRISING AN ELEMENT CONNECTED TO THE BOTTOM OF SAID VERTICAL SHAFT AND RECEIVING IN LATERALLY SLIDING RELATION THE AFOREMENTIONED HORIZONTAL SHAFT SECURED TO SAID HOUSING, AND MEANS FOR PROPELLING SAID CRANE ALONG THE TRACK COMPRISING A MOTOR MOUNTED UPON ONE OF SAID TRUCKS AND HAVING MEANS CONNECTING A POWER SHAFT OF SAID MOTOR TO A FIRST ONE OF SAID AXLES AND POWER TAKE OFF MEANS CONNECTING SAID FIRST AXLE WITH TH SECOND AXLE. 